Molecular Cage Promoted Aerobic Oxidation or Photo-Induced Rearrangement of Spiroepoxy Naphthalenone

Herein, we report a Pd4L2-type molecular cage (1) and catalyzed reactions of spiroepoxy naphthalenone (2) in water, where selective formation of 2-(hydroxymethyl)naphthalene-1,4-dione (3) via aerobic oxidation, or 1-hydroxy-2-naphthaldehyde (4) via photo-induced rearrangement under N-2 have been accomplished. Encapsulation of four molecules of guest 2 within cage 1, i.e., (2)(4)subset of 1, has been confirmed by NMR, and a final host-guest complex of 3 subset of 1 has also been determined by single crystal X-Ray diffraction study. While the photo-induced ring-opening isomerization from 2 to 4 are known, appearance of charge-transfer absorption on the host-guest complex of (2)(4)subset of 1 allows low-power blue LEDs irradiation to promote this process.

Automated summary

This study reported a Pd4L2-type molecular cage and catalyzed reactions of spiroepoxy naphthalenone in water, achieving selective formation of different products. Confirmation of encapsulating guest molecules within the cage and determination of host-guest complex structures were carried out by NMR and single crystal X-ray diffraction study. Appearance of charge-transfer absorption on the host-guest complex enabled low-power blue LEDs irradiation to promote a photo-induced ring-opening isomerization process.